A typical fluid valve provided on a fluid channel, as schematically shown in FIG. 1A, includes a valve body 92, a stem/shaft 94 and a valve disc (not shown) installed inside the valve body 92 and below the stem/shaft 94. The typical fluid valve is controlled to be opened or closed by moving, usually by rotating, the stem/shaft 94 and therefore synchronize the motion of the valve disc (not shown).
The industrial application of the typical fluid valve requires the valve body 92 and the stem/shaft 94 to be resistant to high-temperature and/or corrosive fluids, and therefore requires them to be made of heat-resistant and/or indissoluble materials, such as metals. However, the metal-made valve body 92 and the stem/shaft 94 are easy to form gaps there between when they become worn after mutual friction for a period of time and/or when they are subjected to huge temperature variation, and which easily cause particles to enter the gaps to stick the stem/shaft 94 in the valve body 92. Accordingly, a fluid valve might be improved to be formed with a shaft seal groove 922 between the stem/shaft 94 and the valve body 92, and disposed with several stacked annular shaft seal rings 96 in the shaft seal groove 922, such that the stacked shaft seal rings 96 support and avoid stuck of the stem/shaft 94. It is well known that the stacked shaft seal rings 96 are often made of materials with lower rigidity and smaller thermal expansion coefficients, such as graphite or polytetrafluoroethene (PTFE). Therefore, the above-mentioned problems of forming gaps between the shaft 94 and the valve body 92 due to continuous wear and/or drastic heat expansion and contraction may be reduced.
However, referring to FIG. 1B, the improved fluid valve still has a problem of having unbalanced lateral loading distribution 8 along the axial direction of the stacked shaft seal rings 96, wherein an upper portion of the stacked shaft seal rings 96 is subjected to a larger lateral loading than that to which a lower portion is subjected. Such result could badly affect the sealing effect of the stacked shaft sealing rings. An ideal lateral loading distribution should be that the upmost and lowest portions of the stacked shaft sealing rings are subjected to identical or similar loadings and the loadings gradually decrease towards the center portion. Other improved fluid valves are provided with disc springs and/or coil springs in the shaft sealing structure to balance the lateral loadings. However, the shape of the disc springs subjects the inner ring and the outer ring thereof to unequal axial loadings and could not effectively solve the issue of unbalanced lateral loadings. Although could be used to bear evenly distributed loadings, the coil springs occupy too much space in a shaft sealing structure.
On the other hand, the shaft seal rings 96 could still become worn after a long period of time of usage and/or corroded by corrosive fluid, and gaps may be formed between the shaft 94 and the valve body 92 and cause the fluid to leak. Accordingly, there is a need to periodically clean and/or replace the damaged shaft seal rings 96 within the shaft seal groove 922 to maintain the normal operation of the fluid valve. However, as shown in FIG. 1A, the shaft seal groove 922 is typically a very restricted space that is difficult for technicians to take one of the stacked shaft seal rings 96 and perform the clean and/or the replacement. The time consumed in the clean and/or the replacement of the stacked shaft seal rings 96 not only increases the labor cost but may also cause the production line to shut down when the fluid valves are not available.
In view of the above, there is a need to provide a single shaft-sealing module that contributes ideal lateral and axial loading distribution on the shaft-sealing components disposed inside the single shaft-sealing module, provides convenient cleaning and replacement operation, as well as has small space occupation.